The present invention relates to a method for brazing aluminum components, and more particularly to a method for brazing aluminum components with the efficient use of a flux. In this specification aluminum includes aluminum alloys.
When aluminum components are assembled into a heat exchanger, they are fluxed prior to brazing, except for the vacuum brazing. The heat exchangers include radiators, evaporators, and condensers for car coolers.
Under the common practice a flux is suspended in a water or a solvent, and coated on the surfaces of aluminum components by spraying, by showering or by dipping. After the fluxed surfaces are dried by preheating, the aluminum components are heated to a brazeable temperature in a nonoxidizing atmosphere at which a braze metal melts to effect the braze joints. This method requires at least two preparatory steps: one is to prepare a flux suspension and the other is to coat it on the surfaces of the aluminum components and dry the fluxed surfaces. Thus the preparation takes a longer time, and consumes labor. In addition, a problem is that during drying the aluminum and the water contained in the flux suspension react with each other to form an oxide film, which reduces the brazeability of the braze metal. Another problem is the waste of flux: more specifically, to obtain the flux suspension, a considerable quantity of flux must be added but most of it is left unused and thrown away. There is a further problem resulting from over-fluxing on the components. The leftovers of flux on the surfaces remain as stains. A still further problem arises when the flux is coated on the components which are provisionally assembled with fastening jigs. When the provisional assembly is preheated to dry the fluxed surfaces, the fastening jigs and the components are likely to adhere to each other. In addition, when the jigs are subjected to frequent preheating, the heat fatigues them. When the components include pipes, they must be covered so as not to allow the flux suspension to enter. An extra masking process is required. This also consumes labor, and unfavorably prolongs the time spent in brazing.
The present invention is directed toward an improved method for brazing aluminum components which solves the problems pointed out with respect to the known brazing method. Thus an object of the present invention is to provide a method for brazing aluminum components by a simplified procedure.
According to one aspect of the present invention, there is a method for brazing aluminum components which comprises setting a flux and aluminum components in a furnace filled with a nonoxidizing gaseous medium; thereby suspending the flux in the nonoxidizing gaseous medium; heating the aluminum components to a brazeable temperature; and allowing a braze metal to melt so as to effect the braze joints between the aluminum components.
According to another aspect of the present invention, there is a method of brazing aluminum components, the method comprising filling a brazing furnace with a nonoxidizing gaseous medium; setting a flux in the furnace, thereby allowing the flux to suspend in the nonoxidizing gaseous medium; placing electro-statically fluxed aluminum components in the furnace; and heating the aluminum components to a brazeable temperature, thereby allowing a braze metal to melt and effect the braze joints between the aluminum components.
Other objects and advantages of the present invention will become more apparent from the following detailed description, when taken in conjunction with the accompanying drawings which show, for the purpose of illustration only, one embodiment in accordance with the present invention .